Outlines:-

Introduction

Working principle

Consruction

Types of Transformer

Transformer Auxillaries

Poly phase transformer images

Transformer is an electical device which

transfers electrical power from one electrical

circuit to another electrical circuit without

change of frequency.

Transformer can also step up or step down

the voltage levels.

Without transformer it is not possible to

transfer electrical power from generating

station to customer end.

It is highy efficient electrical device.

Transformer works on the Faraday’s Law of

Electro magnetic Induction same like

induction motor.

But in transformer there is mutual induction

between primary and secondary winding.

Basic construction of transformer is shown in

below fig.

Transformers are classified on basis of

1. Duty they perform

2. Construction

3. Voltage output

4. Application

5. Cooling

6. Input supply

Construction:-

Core type transformer

Shell type transformer

Berry type transformer

Voltage output:-

Step down transformer(Higher to Lower)

Step up transformer(Lower to Higher)

Auto transformer(Variable from ‘0’ to rated

value)

Basic construction of single phase

transformer is shown below that we have

studied in earlier

Duty they perform:-

Power transformer – from transmission and

distribution

Current transformer- instrument

transformers

Potential transformer- instrument

transformers

Poly phase transformer is generally used for

transfer bulk electrical power requirement.

Poly phase transformer are generally three

types:

Station Transformer

Power transformer and

Distribution transformer

Station Transformer

Staterion transformer is used to provide

electrical power to start generating station.

Power Transformer:-

Power transformer is used to transfer bulk

electrical power from generating station to

distribution end.

This transformer has maximum efficiency

compare to other transformer at full load.

It give approx. 99 % efficiency at full load.

Distribution transformer:-

Distribution transformer is used to distribute

electrical power from receive end to final

consumer.

It has law efficiency compare to other

transformer.

It has aprrox. 55 % efficiency.

Station Transformer:-

Power Transformer:-

Distribution transformer:-

There are auxillaris provided in poly phase

transformer for protection purposes as well

as for efficient performance.

Following are the auxillaries provided in poly

phase transformer:

Tank

Conservator

Breather

Bucholz Relay

Tank:-

It provide the mechanical support to themagnetic core as well as other auxillaries likebreather and conservator

Insulation oil or Di-electric oil is filled in thetank

It is made from the non- corrossive iron material

It can be vissible from outside of transformer.

Conservator (Expansion Tank):-

A small auxiliary oil tank mounted above the

transformer and connected to main tank by a

pipe.

Its function is to keep transformer tank full

of oil

Conservator

Breather:-

It is a chamber which prevents entry of moisture inside the transformer tank.

It is filled with drying agent such as calcium chloride or silica gel.

This absorbs moisture and allows dry air to enter transformer tank. It is replaced regularly.

It can be identify by changes of colour. If there is moiture in oil then silica gel becomes pink colour from Blue colour.

Breather

Bucholz Relay:-

First warning that fault is present is given by

presence of bubbles in oil.

It gives an alarm in case of minor fault and to

disconnect transformer

From the supply mains in case of severe faults.

Bucholz relay is used above 100 KVA rating

transformer

Bucholz Relay

Any Querry

?

Thank you !